The technology to process a lower layer under a pattern, by forming a fine pattern on a substrate and performing an etching using the formed pattern as a mask, is adopted for producing an integrated circuit (IC) and the like in the semiconductor industry, and thus it has received great attention. This fine pattern is composed of an organic material, and is formed by using technologies such as photolithographic methods and nano-imprinting methods.
For example, in a photolithographic method, the pattern is formed by using a resist composition containing a resin component. There are two types of resist compositions, that is, a positive resist composition and a negative resist composition.
A coating film composed of a positive resist composition has the property that it is insoluble in an alkali developer before exposure, and changes to be soluble after exposure. A coating film composed of a negative resist composition has the property that it is soluble in an alkali developer before exposure, and changes to be insoluble after exposure.
For example, when a pattern is formed by using a positive resist composition, the positive resist composition is applied and dried, thereby forming a coating film. Next, the coating film is exposed through a mask pattern, and developed using an alkali developer, thereby removing an exposed portion, which is changed to be soluble in the alkali developer. As a result, a pattern is obtained.
Then, using the pattern as a mask, a substrate and the like are processed by etching. As the etching, wet etching or dry etching is used, and of these, dry etching is mainly used (for example, see Patent Document 1).